week 10 Lecture 2

• The global economy is represented as a suspension bridge, the cars flowing represent the money
• Agriculture makes up just 4% of the global GDP - this is dependent on soil, pollinators, climate, and pest control
• We are messing up these 4 factors (soil, pollinators, climate, pest control) which decreases farming and without farming the entire economy shuts down, because people will die
• Soon there will be no food on the shelves for a couple of weeks
• Easter Island - 1200 AD, in 1888 there were no statues left


  The island was divided into 12 smaller kingdoms, working together - each had a leader and each one built statues to honour their leader. As successive leader wanted bigger and better statues so over time they get bigger. The statues are built from one quarry - there is only one place on the island where the material is made from - they had to be transported which is quite difficult.
• Easter Island citizens


  1. Farming and produce farms to increase food output

  2. Expansion occurs because you are only on a small island so the extra food goes towards expansion of more citizens

  3. Excess effort can only go into luxuries e.g. building statues

  4. Resources need to be replenished, and if not it causes ecosystem damage

  5. Population can't increase forever despite the increased energy for farming because it's only a limited island - eventually we may get to a point where the system is damaged and replacement decreases reduces resources - decreasing people on the island
• Tragedy of the commons


  Shared land and anyone can graze there. People start increasing their use of the land. It keeps increasing and the land begins to erode and the resource is destroyed and everyone loses. The costs on the environment are shared by everyone - if you cut your carbon emissions the cost is only on you but the benefit is shared among everyone.
• Ecological footprint


  The average person uses 2.7 hectares of land. It encompasses everything you take and put out into the environment e.g. pollution but also food.
• Ecological footprint per person

  • Africans - 1 hectare
  • USA - 9 hectares
  • Scotland - 5.4 hectares
• The earth can sustainably feed 4.4 billion average people as the earth's farm is 12 billion bioproductive hectares. Therefore we are feeding 2.8 billion unsustainably.
• Unsustainable feeding practices include putting substances onto the land meaning deforestation and fossil fuels and fertilisations and overfishing. This is degrading the environment.
• Demand is increasing as people get richer and population is increasing (overpopulation). The number of people being fed unsustainably is increasing.
• 1/2 of the grain grown in America is grown for animals - this isn't a very efficient way of using the food
• Global soil loss is a major environmental impact of humanity that gets a lot less attention than climate change, deforestation. Without soil we can't grow food.
• Challenge we face


  • We need to provide food and energy to all the people without harming the people of the future. Look after the people today but don't ruin the people of tomorrow.
• Renewable energy


  The solution to providing energy, it's just a matter of scaling it up but we know how to do it
• Agroecology


  Intelligent farming. For example growing ducks and rice together. Ducks control pests and weeds and meat production adds to the total output.
• Agroecology examples


  • Tamback system - alternating rice and shrimp in rotation, the shrimp eat all the rice pests, and as a result there is an output of shrimp and rice with no pests
  • African maize crops - plagued by striga weeds, if you introduce desmodium then this suppresses striga and repels borers and this increases fertilisation of the soil and feeds the livestock
• Functioning ecosystem


  • You increase the useful species and human design and control with minimum maintenance needed. This creates a permaculture (permanent agriculture). It's an ecosystem created by humans with intelligent inputs and diverse outputs. Putting a lot of effort in the first few years and it keeps going like an ecosystem after a while.
• Polyculture


  Efficient use of environment. Many species are grown together at the same time. There is a vast amount of competition - to reduce competition among the crops, the more different crops you have growing in the same area, the less competition and they can support and benefit one another.
• Tikopia


  Agro-ecology and strict population control, 500 hectares they have controlled the whole island to it serves the people. Almost all of the island is covered by useful trees maximised efficiency for supporting people.
• Modern plant science tends to address one problem (golden rice - best thing GM has ever done, rice that contains vitamins that saves lives and help people).
• Permaculture aims to address many problems at once
• Soils are major carbon sinks
• Conventional farming puts carbon dioxide into the atmosphere and erodes away at the soil
• Organic and permaculture farming increases the soil and decreases the carbon from the atmosphere - could offset 1/3 of global emissions.